Add infrastructure to track activitiy relaunches

As a preparation to start synchronizing task size
with activity relaunches, we need a infrastructure
so we know in AM/WM when an activity is relaunching
and when it's done relaunching.

Bug: 26311778
Bug: 25015474
Change-Id: Ied3795eddbcd112f6329494afbf13178ca49a799
diff --git a/core/java/android/app/ActivityManagerNative.java b/core/java/android/app/ActivityManagerNative.java
index 51ce7af..da21099 100644
--- a/core/java/android/app/ActivityManagerNative.java
+++ b/core/java/android/app/ActivityManagerNative.java
@@ -570,6 +570,14 @@
             return true;
         }
 
+        case ACTIVITY_RELAUNCHED_TRANSACTION: {
+            data.enforceInterface(IActivityManager.descriptor);
+            IBinder token = data.readStrongBinder();
+            activityRelaunched(token);
+            reply.writeNoException();
+            return true;
+        }
+
         case GET_CALLING_PACKAGE_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             IBinder token = data.readStrongBinder();
@@ -3413,6 +3421,17 @@
         data.recycle();
         reply.recycle();
     }
+    public void activityRelaunched(IBinder token) throws RemoteException
+    {
+        Parcel data = Parcel.obtain();
+        Parcel reply = Parcel.obtain();
+        data.writeInterfaceToken(IActivityManager.descriptor);
+        data.writeStrongBinder(token);
+        mRemote.transact(ACTIVITY_RELAUNCHED_TRANSACTION, data, reply, 0);
+        reply.readException();
+        data.recycle();
+        reply.recycle();
+    }
     public String getCallingPackage(IBinder token) throws RemoteException
     {
         Parcel data = Parcel.obtain();